A cricketer has a certain average for $10$ innings. In the eleventh inning, he scored $108$ runs, thereby increasing his average by $6$ runs. His new average is

Nine friends have a dinner in a hotel. Eight of them spent $Rs.\, 12$ each on their meals and the ninth spent $Rs. \,16$ more than the average expenditure of all the nine. Find out the total money in $Rs.$ spent by them?

The average age of $6$ members of a family is $20\, years.$ If the age of a servant is included, the average age increased by $25 \%$. What is the age (in $years$) of the servant ?

Eleven years earlier the average age of a family of $4$ members was $28 \,years.$ Now the age of the same family with six members js yet the same, even when $2$ children were born in this period. If they belong to the same parents and the age of the first child at the time of the birth of the younger child was same as there were total family members just after the birth of the youngest member of this family, then the present age of the youngest member of the family is in $year$?

The average weight of $36$ students is $50 \,kg$. It was found later that the figure of $37 \,kg$ was misread as $73 \,kg.$ What is the correct average? (in $kg$)

The average of first three numbers is double of the fourth number. If the average of all the four numbers is $12,$ find the $4^{th}$ number.